Carbon dioxide levels in the atmosphere increased to a record high in 2023, even as countries promise to lower their emissions, the World Meteorological Organization reported Monday.
The WMO, an agency of the United Nations, said in its annual Greenhouse Gas Bulletin that in 2004, the concentration of carbon dioxide in the atmosphere was 377.1 parts per million (ppm), but in 2023, it was 420.0 ppm, an increase of 42.9 ppm, or 11.4%, in just 20 years. Large vegetation fires combined with high levels of human and industrial fossil fuel emission activities in 2023 may have contributed to increasing carbon dioxide emissions, it said.
“Another year. Another record,” said WMO Secretary-General Celeste Saulo. “We are clearly off track to meet the Paris Agreement goal of limiting global warming to well below 2 °C and aiming for 1.5°C above pre-industrial levels.”
Saulo added that the concentration levels will affect humans and the environment.
The report comes out ahead of the 29th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP29) in November, when 198 countries will meet in Baku, Azerbaijan, to negotiate climate plans. The conference was launched in 1992, when countries first committed to lowering greenhouse gas emissions.
Carbon dioxide accounts for the majority of the warming effect on the climate. The report said the annual increase of 2.3ppm marked the 12th consecutive year with an increase greater than 2 ppm, with 2023 being the largest increase of 2.8ppm.
Environmentalists believe the maximum amount of carbon dioxide should be no more than 350 ppm to prevent irreversible impacts on the planet. MN350, an environmental advocacy group, said that adding 2 ppm of carbon each year risks triggering a tipping point in the environment.
“The Bulletin warns that we face a potential vicious cycle. Natural climate variability plays a big role in carbon cycle. But in the near future, climate change itself could cause ecosystems to become larger sources of greenhouse gasses,” said WMO Deputy Secretary-General Ko Barrett.
“Wildfires could release more carbon emissions into the atmosphere, whilst the warmer ocean might absorb less CO2,” he added. “Consequently, more CO2 could stay in the atmosphere to accelerate global warming. These climate feedbacks are critical concerns to human society.”
In addition, methane emissions were lower in 2023 than in 2022 but at a record high for five years, with the majority of the methane coming from sources like fossil fuel exploitation. Nitrous Oxide is another greenhouse gas that had lower concentration levels in 2023 than in 2021.
Meanwhile, the United Nations said Monday that the world is not on track to reach its reduction goals on carbon emissions this decade, as the total of CO2 emissions into the atmosphere in 2030 will only be 2.6% lower than in 2019.